I have a problem. I have an '04 Ram 1500 with the Hemi (192k miles). I pulled up to a gas pump (truck running normally), turned off the truck, filled the tank, got in, turned the key and it wouldn't start! It would turn over and if I floored the gas pedal, it would kinda run. Can't get it to idle or anything. I took it to a mechanic...he replaced the fuel pump, cleaned the throttle body...nothing! I got under it and (if I try to start it enough), the driver's side catalytic converter is cold while the passanger's side is hot. I pulled the O2 sensor from the driver's side, manifold side of the converter and it seemed to run a little. I've got it at a muffler shop now and they called me and said they cut the cats out but, they're not clogged...any ideas on what my issue might be would be greatly appreciated!!! This is getting expensive and I haven't gotten any closer to a resolution!!

Thank you,
Aaron

 

Okay lets start here:

1) What (if any) Modifications do you have done to the truck?

2) Have you tried pulling any DTC (Check Engine Light) codes from the truck? [If Yes what were the codes??]

3) If you just turn the key to the "run" position are any lights on besides the battery light? [If so which?]

4) When you say "kinda starts" what do you mean? Does it run and then shut off or does it sputter and shut right off?

I am going to tentatively say you have suffered some kind of electrical fault, in that the computer itself might be fried for some reason, possibly a short right at the trucks computer may have taken something out, but without trying to pull the codes I can't say for sure what is going on.

This is one of those problems that might be better dealt with at the dealership, where they can actually look at the computer and see if it is working correctly.

Also, Why the heck would you bring a truck that wouldn't start to a muffler shop?? A truck with a clogged cat would still run for the most part...

Anyways answer my questions above and we'll go from there...

 

Thanks for responding, Izero...

1) No mods...only put a K&N airfilter in.
2) Lots of codes...
P0403
P0406
P0113
P2172
P0172
P0175
P0700
P0562
3) No, just the battery light
4) I mean it'll start but, I have to massage the gas to keep it going.

The dealership had the truck for 4 hours then called me to say "we don't know what's wrong but, for $8,600, we can put a reman motor in and that should fix your problems"!!!!

 

Do a compression check. that should tell you if you have something wrong with the motor. I'm thinking head gasket gave out. I had a neon that did that. stopped, fillied it with gas, went inside and paid, got some snacks and I come outside and as I walk up to the car, all of the sudden smoke starts pouring out. Head gasket just gave and flooded the engine...I was able to barely get it to run and make it the half mile down the road to my shop.

 

has the timing chain been changed in the last 100K miles?

 

Stuck injector? I'd ohm injectors maybe do a balance test
Compression test for sure don't know deff of those codes

 

Did a compression check...all cylinders read between 173-180.
Timing chain has never been changed...

 

Didn't check the injectors...has good fuel pressure though! I was thinking that having the one cold catalytic converter could indicate that there's no fire getting to the driver's side cylinders. Oh...something I forgot to mention (probably valuable info), I replaced the spark plugs less than 1000 miles ago...when I took them out, they looked like they had been in there for 70,000 miles! They were completely black, the electrodes had been worn down to where the gap was 55-65, the porcelain was discolored down by the threads (that could be because I used too much anti-seize though)

 

Ouch, well that I would say that might indicate a burnt valve... or a valve problem period... but from your compression test results that really would be nearly impossible...

P0403 - EGR Problem
P0406 - EGR Problem (Circuit High)
P0113 - IAT Malfunction
P2172-HIGH AIRFLOW / VACUUM LEAK DETECTED (INSTANTANEOUS ACCUMULATION)
P0172 - System Too Rich (Bank 1)
P0175 - System Too Rich (Bank 1)
P0700 - Transmission Control System Malfunction
P0562 - SYSTEM VOLTAGE (ENGINE SIDE) TOO LOW

All of these can be caused by a serious electrical problem, Your Alternator and Battery might be shot, or you may have had a massive short somewhere that fried the computer and/or all of the main engine/computer grounds.

I don't think this is a "mechanical" problem anymore, I am starting to think its a VERY serious electrical problem.

Here's what I would do:

1) Pull the PCM/ECU and look at ALL of the plugs, if you see ANY discoloration then you know what happened. Electrical Short caused a short circuit and fried the Computer or just damaged the connectors and grounds to the extent that the engine is preventing the truck from starting.

2) If Computer & Connections look good, get a voltage meter and set it up from the positive battery terminal to the chassis, then try and start the truck, see where the Voltage goes to, if it is much lower than 11V then you have a bad alternator and/or short on the main harness. If it is high then your alternator's voltage regulation system may have failed.

3) Bring it to the dealer and let them really get into it, but that will cost a pretty penny to have them do, but they can easily plug in with a starscan tool and see if the computer is even responding, they may even be able to pull codes your truck isn't showing for you.

Let us know how 1 & 2 turn out...


----------------------------------------------------------------------------

Alright I read into the P2172 problem and that problem by itself can cause the computer to not allow the truck to start, so here is how you troubleshoot that code:

P2172-HIGH AIRFLOW/VACUUM LEAK DETECTED (INSTANTANEOUS ACCUMULATION)


Possible Causes
VACUUM LEAK
RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT
(K1) MAP SIGNAL CIRCUIT SHORTED TO GROUND
RESISTANCE IN (K900) SENSOR GROUND CIRCUIT
RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE TP SENSOR SIGNAL CIRCUIT
TP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K922) TP SENSOR RETURN CIRCUIT
MAP SENSOR
TP SENSOR

PCM


Diagnostic Test

1. ACTIVE DTC
NOTE: The most likely cause of this DTC is a vacuum leak.
NOTE: Diagnose any 5-Volt Supply, TP Sensor, Fuel System Lean or Rich, or MAP Sensor DTCs before continuing.
NOTE: The throttle plate should be free from binding and carbon build up.

Ignition on, engine not running.

With a scan tool, read DTCs.
Is the DTC active at this time?
Yes>> Go To 2
No>> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 9 - 818 ENGINE ELECTRICAL DIAGNOSTICS LX

2. VACUUM LEAK
NOTE: This code is enabled on engines with a plastic intake manifold and is intended to limit the maximum engine speed if a large crack occurs.
NOTE: A large vacuum leak is most likely the cause of this DTC.
Inspect the Intake Manifold and Throttle body for leaks and cracks.
Inspect the Power Brake Booster for any vacuum leaks.
Inspect the PCV system for proper operation or any vacuum leaks.
Inspect the MAP Sensor for proper installation.

Were any vacuum leaks found?
Yes>> Repair the vacuum leak as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>> Go To 3

3. MAP SENSOR OPERATION
Start the engine.
With a scan tool, monitor the MAP Sensor voltage.
Snap the Accelerator pedal.

Does the MAP Sensor voltage vary from below 2.0 volts at idle to above 3.5 volts at Wide Open Throttle?
Yes>> Go To 4
No>> Go To 11

4. TP SENSOR OPERATION
Ignition on, engine not running.
With a scan tool, perform the Throttle Follower Test.
TP Sensor No.1 should start at approximately 0.8 of a volt and increase to 4.2 volts.
TP Sensor No.2 should start at approximately 4.2 volts and decrease to 0.8 of a volt.

Is the voltage transition smooth between the appropriate values?
Yes >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>> Go To 5 LX ENGINE ELECTRICAL DIAGNOSTICS 9 - 819

5. RESISTANCE IN (F855) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the Throttle Body harness connector.
Disconnect the PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (F855) 5-volt Supply circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance above 100 ohms?
Yes>> Go To 6
No>> Repair the excessive resistance in the (F855) 5-volt Supply circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

6. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and (F855) 5-volt Supply circuit
at the appropriate terminal of the special tool #8815.

Is the resistance above 100 ohms?
Yes>> Go To 7
No>> Repair the short to ground in the (F855) 5-volt Supply circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
9 - 820 ENGINE ELECTRICAL DIAGNOSTICS LX

7. TP SENSOR
Connect the PCM harness connector.
Ignition on, engine not running.
With a scan tool, monitor the TP Sensor voltage.
Connect a jumper wire between the (K22) TP Sensor No.1 Signal circuit and the (K922) Sensor Return circuit in the Throttle Body harness connector.
TP Sensor No.1 voltage should start at approximately 4.8 volts and
decrease to 0.2 of a volt.
Connect a jumper wire between the (K122) TP Sensor No.2 Signal circuit
and the (F855) 5-volt Supply circuit in the Throttle Body harness
connector.
TP Sensor No.2 voltage should start at approximately 0 volts and
increase to 4.8 to 5.2 volts.

Does the TP Sensor voltage change to the appropriate voltage
with the jumper wire installed?
Yes>> Disconnect the Battery before replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>> Go To 8 LX ENGINE ELECTRICAL DIAGNOSTICS 9 - 821

8. RESISTANCE IN THE TP SENSOR SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the PCM harness connector.
Measure the resistance of the (K22) and (K122) TP Signal circuits from the Throttle Body harness connector to the appropriate terminals of special tool #8815.

Is the resistance below 5.0 ohms for each circuit?
Yes>> Go To 9
No>> Repair the excessive resistance in the (K22) or (K122) TP Sensor Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 9 - 822 ENGINE ELECTRICAL DIAGNOSTICS LX

9. TP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K22) and (K122) TP
Signal circuits at the appropriate terminal of the special tool #8815.

Is the resistance above 100 ohms for each circuit?
Yes >> Go To 10
No >> Repair the short to ground in the (K22) or (K122) TP Sensor Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) LX ENGINE ELECTRICAL DIAGNOSTICS 9 - 823

10. RESISTANCE IN THE (K922) SENSOR RETURN CIRCUIT
Measure the resistance of the (K922) Sensor Return circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?
Yes>> Go To 17
No>> Repair the excessive resistance in the (K922) Sensor Return circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

11. RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the MAP Sensor harness connector.
Disconnect the C1/A PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (F856) 5-volt Supply circuit from theMAP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?
Yes>> Go To 12
No>> Repair the excessive resistance in the (F856) 5-volt Supply circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 9 - 824 ENGINE ELECTRICAL DIAGNOSTICS LX

12. (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (F856) 5-volt Supply
circuit in the MAP Sensor harness connector.

Is the resistance above 100k ohms?
Yes>> Go To 13
No>> Repair the short to ground in the (F856) 5-volt Supply circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

13. MAP SENSOR
Connect the PCM harness connectors.
Ignition on, engine not running.
With a scan tool, monitor the MAP Sensor voltage.
Connect a jumper wire between the (K1) MAP Signal circuit and the (K900) Sensor ground circuit in the MAP Sensor harness connector.
Cycle the ignition switch from off to on.
With a scan tool, monitor the MAP Sensor voltage.

Does the scan tool display MAP voltage from approximately 4.9 volts to below 0.5 volt with the jumper wire installed?
Yes>> Replace the MAP Sensor. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>> Go To 14

NOTE: Remove the jumper wire before continuing. LX ENGINE ELECTRICAL DIAGNOSTICS 9 - 825

14. RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the PCM harness connector.
Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?
Yes>> Go To 15
No>> Repair the excessive resistance in the (K1) MAP Signal circuit Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

15. (K1) MAP SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K1) MAP Signal circuit in the MAP Sensor harness connector.

Is the resistance above 100k ohms?
Yes>> Go To 16
No>> Repair the short to ground in the (K1) MAP Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 9 - 826 ENGINE ELECTRICAL DIAGNOSTICS LX

16. RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?
Yes >> Go To 17
No>> Repair the excessive resistance in the (K900) Sensor ground circuit. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

17. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?
Yes>> Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>> Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

 

Wow!!! I really appreciate the time you've obviously put into my problem!
I'll work on it this weekend and keep y'all posted

Thank you!
Aaron